Put a group of women in a room together and chances are they will be discussing sex, husbands, diets and childcare in no time.

It's just as likely that they will have wildly diverging beliefs, so a book collating the opinions of thousands of women on these subjects could turn into a cacophony of voices. Thankfully, What Women Know by Irish authors Michelle Jackson and Dr Juliet Bressan is a much calmer affair.

Bressan and Jackson know a thing or two about life and love but they leave the advice to the online community of women that popped up as a result of their research.

LOVE AND SEX

Love and sex don't always go together. They often don't even go in that order. The authors suggest that multi-tasking women who lack energy for their love life should stop and think about how much time they spend tending to their homes, their children, their careers and compare that with how much they tend to their sex lives.

A young nurse tells a cautionary tale. "There was the time that my fiance prepared a surprise for me . . . a room full of lit tea lights, Marvin Gaye playing, sparkling wine, massage oil and decadent sheets. But I came home stressed out and so tired that I just wanted to go up to bed to sleep! That was three years ago and it's not really any surprise that he's never tried all that since."

As the authors point out, you'll never regret a night of passion with a loved one no matter how tired you are.

Mary (64) simplifies it: "There are only two kinds of sex -- good sex and bad sex," while Ann takes inspiration from the toning effects of the act: "An orgasm is much more fun than pelvic floor muscles exercising."

Pilates, be damned. Gloria, too, finds motivation in the beneficial effects of sex, saying: "There's a very good reason to indulge your partner when he asks for oral sex -- apparently it is the best way to exercise the muscle under your chin and help prevent it from becoming saggy and a double chin!"

For most women, getting married is one of the most momentous decisions they will ever make. When it comes to advice on whether to ditch or to hitch, a Cork woman gives some no-nonsense advice: "If you can't imagine living without him in 10 years, consider marrying him. If you can't imagine living with him in 10 years, lose him! Dead easy."

While Valerie from Kildare puts her faith in the level of arguments: "When a girl or man can't be bothered to have a tiff any more . . . you just know it's over!"

As for the secret to a happy marriage, Janet in Dublin says it is in maintaining your independence, while Grainne says: "If your husband stacks the dishwasher incorrectly -- or not the way you do it -- leave him to do it his way. At least he is making an effort. Same goes for nappy changing, cooking and anything else involved in the home!"

WORK AND MONEY

A recent survey showed that single women rated financial independence above all as the most important factor in their lives. It's easy to see why.

"A lack of finance can prevent women from the freedom to escape dangerous or abusive relationships." While Saniya's most valuable possession is her freedom -- "priceless."

Much is made of the 'glass ceiling' or the imaginary cap to a woman's career progress, usually caused by childbearing.

Marie in Derry says: "If you have self-belief, then there is no glass ceiling, the sky's the limit. You just have to be driven and motivated enough to strive for what you want in life."

Women are famous for the ability to multi-task but Vivienne has a hunch we have been duped: "I don't believe that women are better at multi-tasking than men. It's just a myth that was made up to try to get women to do 10 different jobs at the same time!"

FRIENDSHIP

The frenemy is a term that has become common parlance over the last decade and most of us have had experience of 'toxic friendships'. Keelin, a psychologist from Dublin, puts it simply: "A friend is not a friend when you feel like crap after talking to them."

Another dangerous friendship can be that between a man and a woman, especially if sex comes into the equation. Emma defines the dilemma saying: "I don't find it difficult to be friends with a guy as long as I am not attracted to him!"

Lynne describes a common experience: "I can't count the number of male friends I've lost when they eventually meet a girl and settle down with them. And I wouldn't like my partner to come home to tell me he'd met a fantastic new female friend!"

BEAUTY AND AGEING

In a world where youth is valued above all else, it can be difficult for a woman to accept growing old.

Marie from Belfast says: "Never feel like you're past it. I turned 60 this year and feel like I've never looked better. Always make an effort -- you'll feel like a million dollars."

Sinead, a 75-year-old from Dublin, says: "Sometimes, I hate having to slow down, hate aches and pains, hate grey hair and toothache and wearing glasses and not being able to hear properly . . . but not for long, because I absolutely love wisdom, confidence, peace and all the pleasure you get from your own company in old age -- and really that's all I care about when I come to think of it. If something hurts, I just take painkillers and have a glass of wine and put my feet up for the night."

If your area of concern is your sagging chin, however, you can always try Gloria's advice.